[2] [2] P. Jingjong. Fiberoptic liquid crystal on-off switch and variable attenuator[P]. United States Patent: 2001:6181846

[3] [3] V. Morozov, H. Fan, L. Eldada et al.. Fused fiber optic variable attenuator[C]. OFC′2000, 2000, 25(Supplmenet)： 22～24

[4] [4] Q. Li, A. A. Au, C. H. Lin et al.. An efficient all-fiber variable optical attenuator via acoustooptic mode coupling[J]. IEEE Photonics Tech. Lett., 2002,14(11)： 1563～1565

[5] [5] J. E. Ford, J. A. Walker, D. S. Greywall et al.. Micromechanical fiber-optic attenuator with 3μs response[J]. J. Lightwave Technol., 1998, 16(9)： 1663～1670

[6] [6] R. R. A. Syms, H. Zou, J. Stagg et al.. Multistate latching MEMS variable optical attenuator[J]. IEEE Photonics Technol. Lett., 2004, 16(1)：191～193

[8] [8] Y. O. Noh, C. H. Lee, J. M. Kim et al.. Polymer waveguide variable optical attenuator and its reliability[J]. Opt. Commun., 2004, 242(4～6)： 533～540

[9] [9] Y. Y. Kim, S. S. Yun, C. S. Park et al.. Refractive variable optical attenuator fabricated by silicon deep reactive ion etching[J]. IEEE Photonics Technol. Lett., 2004, 16(2)： 485～487

[12] [12] J. Rheims, J. Kser, T. Wriedt. Refractive-index measurements in the near-IR using an Abbe refractometer[J]. Meas. Sci. Technol., 1997,8(6)： 601～605